Capacitive Touch Keyboard With Hover And Pressure Sensing
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Solution Overview
Problem
Existing keyboards rely solely on key contact to detect input, limiting their ability to sense hover, contact, and pressure, and thus fail to provide comprehensive user interaction data.
Innovation Solution
The development of capacitive touch sensors that utilize orthogonal signaling techniques, such as frequency-division multiplexing or code-division multiplexing, to detect touch events with high sensitivity, allowing for the differentiation of hover, contact, and pressure levels without physical contact, and enabling the reconstruction of user gestures and interactions in real-world and virtual reality settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional key contact detection methods are used, then the keyboard structure remains simple, but the ability to sense hover, contact, and pressure is limited
Solution Approach 1:
The keyboard surface is divided into multiple independent capacitive sensing zones, each capable of detecting touch events separately. This segmentation allows precise localization of hover, contact, and pressure events at specific key positions while maintaining overall system simplicity through modular sensor architecture
Solution Approach 2:
The capacitive sensor system performs multiple detection functions simultaneously - detecting hover states, contact events, and pressure levels - using a single unified sensor architecture. This multi-functionality eliminates the need for separate sensor systems for each detection type, resolving the contradiction between measurement precision and device complexity
2Loss of information
If only key contact is detected, then the device complexity is low, but the quantity of user interaction information is insufficient
Solution Approach 1:
The sensor system dynamically adapts its detection capabilities by adjusting sensitivity thresholds and detection parameters based on the current state (hover, contact, or pressure). This dynamic operation enables comprehensive capture of user interaction information across different touch phases without requiring permanently complex sensor configurations for all detection types
Solution Approach 2:
The system uses feedback from capacitive coupling changes to distinguish between hover, contact, and pressure states. By continuously monitoring capacitance variations and comparing them against calibrated thresholds, the system recovers complete user interaction information while maintaining relatively simple sensor hardware through intelligent signal processing
3Adaptability or versatility
If capacitive touch sensors with orthogonal signaling are implemented, then hover, contact, and pressure detection is enabled, but the device complexity increases
Solution Approach 1:
The system employs periodic orthogonal signaling sequences to excite the capacitive sensor array, allowing multiplexed detection of multiple touch parameters through time-divided signal transmission. This periodic approach enables versatile interaction mode detection while managing signal processing complexity through structured, repeating signal patterns that simplify receiver design
Solution Approach 2:
The system detects different interaction modes by measuring changes in capacitive coupling parameters at different frequencies and phases of the orthogonal signaling cycle. By analyzing parameter variations across multiple signal dimensions, the system achieves versatile interaction detection capability while keeping the physical sensor structure relatively simple through electronic parameter differentiation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables advanced user interaction capabilities by providing granular, multi-level information on finger positions and pressures, allowing for precise reconstruction of user interactions in virtual reality and augmented reality environments, enhancing the usability of keyboards in these settings.
Implementation Method 1
a capacitive object, including, e.g., a user's finger, hand, or forearm, or a stylus, is detected by a touch detector formed using a transmit antenna and a receive antenna. In operation, a signal is transmitted onto the transmit antenna and a receiver receives signals present on the receive antenna to determine an amount corresponding to each of the plurality of signals transmitted onto the transmit antenna. A signal processor analyzes the received signal to determine a touch event, including at least one of hover, contact, and pressure, based on changes in the amount of the signal transmitted onto the transmit antenna that is present in the received signal
Data Source
AI summary
A touch sensitive keyboard is disclosed. In one embodiment, a touch sensitive keyboard is provided that has a touchpad area separate from the keyboard keys. The keyboard is configured to disabled touchpad sensitivity when certain touch signals are received. In another embodiment, a touch sensitive keyboard is used as a controller. In a controller mode, keys on a touch sensitive keyboard are adapted to output a signal strength corresponding to a distance between the key and a finger operating as a control. In an embodiment, a touch sensitive keyboard includes a processor adapted to output a keystroke in response to one of the plurality of touch sensitive keys being pressed, and to output one or more touch points determined by interpolating signal strength for each of the plurality of touch sensitive keys on the keyboard.